Production of sodium hydroxid.



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To all whom it may concern." I

]Be it known that 1, CHARLES S. BnAnLnY, a citizen of the United States, residing in the city, county, and State of New York,

.have invented certain new and useful Improvements in the Production of Sodium Hydroxid, of which the following s a. full and clear specification.

employ a 0 My invention relates in general to the production of sodium hydroxid and allied products and has for its ob ect to produce such products with the aid of materials which are for the most part inexpensive, and

to regenerate and conserve the more expensive reagents and materials employed in the process. According to my process I 'eap reagent for the greater portion of the causticizing step and beyond the ability of this reagent to perform the causticizing stepI employ a more expensive and powerful reagent which is regenerated over I and over again in the process and which hence may be employed without loss of economy. In this way I gain a substantially complete efficiency of the causticizmg operation, and obtain a high degree of purity in the product.

chlorid solution and ammonia gas, carbon dioxid and water, as follows:

The water is omitted in the above equation, for simplicity. This reaction 1s endo- 1 thermic' and absorbs in the neighborhood of 17000 heat units. In order to avoid the inefficiency'of supplying these heat units from a source outside of the system, I may employ a heat conservation process in which advantage is taken ofthe heat envolved in a subsequent exothermic chemical action, to

Specification of Letters ltatent.

. Patented Dec; ii. Tait.

' Application filed February 26, 1915. Serial no. 10,733.

supply the rejected heat of the subsequent reaction to the materials taking part in the endothermlc action. Such a conservation process forms the subject matter of another application Serial No. 10,7 32, filed Feb. 26th 1915, and is not claimed, per se, herein. 1i may briefly state, however, that it involves the performance of' the two reactions in heat conductive relation .with each other, the gaseous products from the first reaction being pumped at higher pressure and temperature 111to an exothermic reaction chamber in heat conductive relation with the first reaction, where the heat units previously absorbed are substantially restored. The higher temperature and pressure give rise to the subsequent exothermic reaction which in the present case may be represented as follows: 7

In the formation bf the ammonium carbonate, a quantity of chemical heat is given off which is substantially equivalent to that absorbed in the first reaction and this heat 1s transferred thereto and thus conserved withln the system. The ammonium car- 'bonate is obtained in the-form of a solution in the second chamber and is subjected to the action of sodium chlorid for the production of sodium bicarbonate and ammonium chlorid. This step may be performed in conjunction with the corresponding step in the. ammonia soda process in which case the reaction may be represented as follows:

v, The ammonium chlorid is thus regenerated for the first reaction. The sodium bicarbonate after treatment by well known methods to reduce it to normal carbonate is according 'to the present embodiment of my invention subjected to the causticizing step for the production of caustic soda. This causticizing step is for the greater part accomplished by the aid of lime, as follows: IV. Na GO +CaO H =CaCO -j-2NaOH.

The calcium hydroxid will causticize about 90% of the sodium carbonate and to complete the production of caustic soda and ob tain a substantially pure product I first filter off the s lu i n a d en treat i i h barium hydroxid. Considering only the reerated, and the sodium hydroxid or caustic maining sodiumcarbonate in the solution the reactlon may be represented as follows- The barium carbonate is thus regenerated for the first reaction. The barium hydroxid employed in this completion of the causticizing step is produced Within the system from the by-product' barium chlorid of the first reaction reacting with an equivalent quantity of the caustic soda, produced by the may be representedprocess. This reaction as follows:

It Will be seen of my invention that sodium chlorid limestone are the only raw materials, ex-

cepting Water represented in the chemical process. The barium carbonate and ammonium chlorid are substantially all regensoda represents only the consumption. of common salt, lime and Water. The product, caustic soda, obtained in the manner described, is the result ofa substantially complete reaction, being correspondingly pure and, representing approximately maximum efliciency of production' The requirement for" supplying considerable outside heat to support endothermic reaction between barium carbonate and sodium chlorid is sub stantially avoided by conducting this operation 1n heat conductive relation With a subsequent exothermic product'on of ammonium carbonate, while at the occurrence of objectionable high temperature and the discharge-of Waste heat from the system with consequent loss of efliciency connected With the production of the ammonlum carbonatefis substantially avoided.

The sodium hydroxid is obtained as a product major portion-of the eausticizing step and the barium carbonate produced from the above example and same time the assen in the completion of thisstep being highly insoluble salts and thus insuring high cili cienc'y and complete separation by filtration or otherwise of the caustic soda from the byproducts of the reactions.

I claim:

1. The method of producing soda products which comprises causing a reaction be tween analkallne earth carbonate and ummonlum chlorid for the first reaction, and securing the required barlum hydroxid from the barium chlorid of the first reaction by means of caustic soda obtained by the method.

3. The method of producing soda products which com rises utilizing barium carbonate and ammon um ClllOllCl as starting 

